1. Field of the Invention
The present Invention relates to a method and apparatus for inputting or communication of symbols, such as alpha-numeric characters, using a motion and touch detecting surface.
2. Description of the Related Art
The human mind communicates with the world through the muscular contractions that result in speech and gestures. The human hand is capable of precise, complex motion and has great potential as a means of communication.
Previous attempts to exploit hand motion as a mode of communication have resulted in methods that are relatively slow and cumbersome. The typewriter was the first successful mechanical device using hand movements to communicate complex thoughts. The design of the familiar typewriter keyboard was constrained by mechanical considerations. With the advent of computers, the mechanical considerations disappeared, but the typewriter keyboard remained. A modified typewriter keyboard was combined with a computer mouse and adopted as the human-to-machine interface of choice. No subsequent challenges compromised the dominant role of the keyboard/mouse combination.
There are two reasons for the lasting appeal of the familiar typewriter keyboard. First, the keyboard may be used by an untrained operator and typing skills may be acquired gradually. Second, a skilled typist may produce text very rapidly. To achieve a high rate of typing speed, the skilled typist utilizes the propensity of the brain for parallel processing in which separate neural networks control the motion of each finger. As the typist learns to type, combinations of movements become preprogrammed sequences of neural commands. As the skilled typist works, the preprogrammed movements are stacked in the brain circuits ready for subsequent subconscious execution. By distributing the work load between the two hands and among the ten fingers, the skilled typist may produce text at a speed matching the pace of casual speech.
The typewriter keyboard has several disadvantages. First, a full-size keyboard suitable for high-speed operation is bulky and not easily transported. Second, the keyboard must be operated with both hands to achieve speed and accuracy. Third, the typist must conform his or her posture to the requirements of the keyboard; namely, sitting or standing facing the keyboard with the keyboard at the proper height and angle.
Several improvements to the typewriter keyboard have been proposed. Among the most notable is the chorded keyboard. The user of a chorded keyboard strikes multiple keys using multiple fingers at one time to enter a single character. The advantage of the chorded keyboard is that far fewer keys are needed, allowing the chorded keyboard to be used with one hand. A chorded keyboard may be hand-mounted or hand-held and may be operated away from the desk. Chorded keyboards require complex encoding schemes and complex, multidimensional, multi-joint finger motions and require a return to a resting position following each encoding motion. As a result, chorded keyboards can be operated only at a low speed, even by a skilled operator.
Virtual keyboards are available and are smaller and less obtrusive than the bulky physical keyboard. Virtual keyboards emulate typewriter keyboard operation, including the typewriter keyboard layout. Virtual keyboards employ remote sensing technologies to track finger motions with finger motion tracking devices placed in front of the keyboard or mounted on the hand. The user performs the hand movements of typing on a tabletop and the motion tracking devices translate the finger motions into the keystrokes of a typewriter.
Virtual keyboards share many of the disadvantages of the physical keyboard; namely, a tabletop area is required for operation, the operator must adopt a posture in front of the virtual keyboard, and the operator must type using two hands to achieve rapid operation. An additional disadvantage of the virtual keyboard is the lack of tactile feedback to the user.
Patents related to virtual keyboard technology include U.S. Pat. No. 6,304,840 to Vance issued Oct. 1, 2001 entitled “Fingerless glove for interacting with data processing system” and U.S. Pat. No. 5,767,842 to Koch, issued Jun. 16, 1998, entitled “Method and device for optical input of commands or data.” Virtual keyboard devices are marketed by Samsung Scurry and may be seen on the company website at www.samsung.com. Another virtual keyboard device is marketed by Senseboard Technologies and can be viewed on the company website at www.senseboard.com. The company ‘Virtual Devices’ also markets a virtual keyboard.
Prior art devices for sign language gesture recognition are based on similar principles and provide for free space hand motion tracking.
Touch sensitive tablets or display overlays also have been developed. Touch sensitive tablets may use a typewriter keyboard layout or a chorded keyboard layout and may add enhancements unavailable in a physical keyboard, mostly through integrating the functions of a keyboard and of a cursor positioning device.
Several touch-sensing and proximity detection technologies are well known in the art; among those technologies are membrane or mechanical switches, resistive membranes, acoustic, capacitive, inductive and optical sensors. Many of these devices use a row and column grid of intersecting conductors or similarly arranged matrix of individual sensing elements. Capacitive sensing technology is among the most popular because it is capable of sensing the presence of a finger up to several millimeters away from a sensing device (“proximity sensing”). Capacitive sensing technology allows for zero-force, virtually touchless data entry or manipulation of an object on a screen.
Several multi-finger contact detectors have been proposed. Most are based on capacitive sensing technology. Multi-finger contact detectors are capable of detecting multi-finger-coordinated gestures and are designed for manipulative interactions with complex applications. Examples of such multi-finger contact detectors are as follows:
S. Lee, “A Fast Multiple-Touch-Sensitive Input Device”, University of Toronto Master's Thesis (1984);
U.S. Pat. No. 5,194,862 to Edwards issued Mar. 16, 1993 entitled “Touch sensor array systems and display systems incorporating such”;
U.S. Pat. No. 5,463,388 to Boie issued Oct. 31, 1995, “Computer mouse or keyboard input device utilizing capacitive sensors”;
U.S. Pat. No. 5,844,506 to Binstead issued Dec. 1, 1998 and entitled “Multiple input proximity detector and touchpad system”; and
U.S. Pat. No. 5,825,352 to Bisset issued on Oct. 20, 1998, entitled “Multiple finger contact sensing method for emulating mouse buttons and mouse operations on a touch sensor pad”.
Additional developments have been directed to integrate different types of manual input. Typing, manipulation and handwriting capacities are taught by U.S. Pat. No. 6,323,846 to Westerman issued on Nov. 27, 2001, entitled “Method and apparatus for integrating manual input.”
Each of the prior art approaches reviewed above has one or more of the following disadvantages:
(a) the approach requires conformation to the posture required by the keyboard (typewriter keyboard, virtual keyboard);
(b) the approach does not provide good tactile feedback (virtual keyboard).
(c) the approach involves complex multi-joint, unnatural motions, resulting in slow output (chorded keyboards);
(d) the approach requires forceful, large-amplitude hand 12 motions followed by wasted motion to the neutral resting position (chorded keyboard);
The apparatus and method of the present Invention overcome the foregoing disadvantages of the prior art.